In the field of optoelectronic and semiconductor industries, it is a common manufacturing process to deposit thin film onto ceramic, plastic or glass substrates. Usually, a half-finished product of thin-film substrate would then be processed with a thermal control process, such as a heating process, so as to improve the quality of thin-film products.
The substrates, where thin films are deposited, may be formed of a single material or multiple materials. For example, a substrate is formed of one material for its middle portion and the other material for its two side portions, such that the thermostability of the middle portion is different from the thermostability of the side portions.